Toxic Runoff: How Fertilizers Are Poisoning Florida’s Waterways

Florida is no stranger to nutrient-rich soils—phosphorus occurs naturally in much of the state’s terrain. But when excess phosphorus and nitrogen are introduced into the environment, the consequences for water quality, ecosystems, and human health can be devastating.
The Source of the Problem

Nutrient pollution occurs when fertilizers, animal manure, stormwater runoff, wastewater, and even household products like soap wash into nearby lakes, rivers, and coastal waters. These pollutants often contain high levels of phosphorus and nitrogen, which can fuel the growth of harmful algal blooms and degrade water quality.

Major contributors to this runoff include:

• Agricultural lands using chemical fertilizers
• Septic tank leaks
• Urban landscaping and golf courses
• Lawns and parks—including those around Orlando theme parks
• Soil erosion and unfiltered stormwater

Toxic Algal Blooms and Health Hazards

One of the most dangerous outcomes of excess phosphorus is the emergence of cyanobacteria blooms, commonly known as blue-green algae. These blooms can release toxins harmful to humans and animals, contaminate drinking water sources, and cause ecological collapse by depleting oxygen in aquatic environments.

Long-Term Health Risks:

• Neurotoxins like BMAA, produced by cyanobacteria, have been linked to neurodegenerative diseases such as ALS (Lou Gehrig's disease) and may cause brain changes resembling Alzheimer’s.
• Prolonged exposure can affect liver and kidney function, and short-term contact with contaminated water can cause skin rashes, respiratory issues, and gastrointestinal illness.

Florida's Troubled Waters

For decades, runoff from agriculture has sent heavy loads of phosphorus into Lake Okeechobee and the Everglades. This has fueled algal blooms that kill fish, destroy habitats, and threaten wildlife. In 1988, the federal government even sued the state of Florida for failing to control phosphorus contamination.

In response, the state created Stormwater Treatment Areas—artificial wetlands built on former farmlands—to help filter out pollutants before they reach natural ecosystems.

Solutions and What You Can Do

While Florida has made strides in addressing nutrient pollution, there’s still a long way to go. Effective solutions include:

• Limiting pollution at its source (e.g., reducing fertilizer use)
• Strengthening environmental laws and enforcement
• Establishing health-protective limits on nutrient pollution
• Educating the public on the impact of everyday products and practices

Personal Action Steps:

• Use phosphorus-free fertilizers and detergents
• Maintain septic systems properly
• Reduce lawn chemical use and plant native vegetation
• Support environmental organizations and advocate for clean water policies

Recommended Reading

Environmental Florida: Troubled Waters
FIU News: There's Too Much Nitrogen and Phosphorus in U.S. Waterways
University of Florida: Phosphorus & Soil Testing Resources
WWF: Over 80% of Marine Pollution Comes From Land-Based Activities

Clean water starts with informed action. By understanding the causes and consequences of phosphorus and nitrogen pollution, we can work together to protect Florida’s waterways, ecosystems, and communities.